Underwater safety connector



March 3, 1970 A. H. DROUIN UNDERWATER SAFETY CONNECTOR 7 2 Sheets-Sheet 1 Filed Nov. 14. 1967 INVENTOR.

March 3, 1970 A. H. D'RO U'IN 3,493,374

UNDERWATER SAFETY CONNECTOR Filed Nov. 14. 196-7 2 Sheets-Sheet 2 Z INVENTOR. I

United States Patent 3,498,374 UNDERWATER SAFETY CONNECTOR Andre H. Drouin, Houston, Tex., assignor to Rockwell Manufacturing Company, Houston, Tex., a corporation of Pennsylvania Filed Nov. 14, 1967, Ser. No. 682,765 Int. Cl. E21]: 7/12, 41/00; F16] 35/00 U.S. Cl. 166.5 15 Claims ABSTRACT OF THE DISCLOSURE A safety connector for connection between an underwater wellhead in an oil or gas well and its production platform. The connector comprises two main parts which are connected just above the underwater Christmas tree. The lower part is rigidly connected to the tree or made integral therewith. The upper part is connected to the support members of the platform. The lower part of the safety connector is bored to provide for tubing runs and access to casing annulus if desired. The upper portions of these bores are enlarged to receive a mating nipple screwed into the upper part of the safety connector. The upper face of the lower part has groups of hydraulic sockets arranged at approximately 90 degree intervals around the face. Each group contains a number of sockets equal to the number of hydraulic functions performed at the Christmas tree. The sockets representing the same hydraulic function in each group are connected by suitable cross-drilling. The upper part of the safety connector has nipples substantially shorter than the tubing run nipples, which register with the hydraulic sockets of the lower part. All nipples are solid except for the ones in line with hydraulic runs which run to hydraulic fail-safe operators of the Christmas tree valves. The upper part of the safety connector includes connection means for production tubing and hydraulic lines which extend to the platform above water. An outside marine riser may also be connected to the upper part for extension to the platform. The mating upper and lower parts of the safety connector are connected by studs and nuts in a flanged connection. These studs and nuts are of a selected material whose yield and ultimate strength are very close to their normal load. No equipment below the safety connector is connected to the platform legs or braces. Only the upper part of the safety connector and above equipment are anchored to the platform and are subject to the stresses therein.

BACKGROUND OF THE INVENTION Field of the invention This invention is related to offshore production of petroleum products. More specifically, it is concerned with apparatus for completing an underwater well which has a production platform above water.

Description of the prior art For the past several years, a considerable interest has been shown in the offshore drilling and completion of oil and gas wells. A variety of methods and apparatus has been used in completing these wells. One of the most common methods of completion is the production platform method where the production tubing is extended to the surface and connected to a flowline at the platform. This method has always been popular in relatively shallow water and is now being used even in relatively deep water.

One of the disadvantages of the production platform completion method is that the platform may be severely damaged and even turned over through collision with a vessel or by storms, hurricanes, etc. Of course, if this happens, there is a likelihood that the production tree 3,498,374 Patented Mar. 3, 1970 ICC or string will be ruptured. This results in great losses of money and time as well as endangering the lives of those who attempt to repair such a well.

Developments have meen made allowing the completion of wells on the ocean floor without installing a production platform. However, the equipment required is very expensive and other problems, such as occur in maintaining the well, are created in the use of these methods.

SUMMARY The present invention allows enjoyment of the advantages of a production platform without the normal disadvantages arising in the case of collision, storms and hurricane damage. The safety connector of the invention allows the platform to be completely blown over without opening the well and losing production. It also allows quick and relatively inexpensive reconnection for continued production.

In the present invention a safety connector device is installed just above the underwater Christmas tree of a well and communicating with the production string. Tubing and a marine protection riser, if desired, extends upwardly from the safety connector to the platform. The connector comprises two major parts. The lower part is connected to the underwater Christmas tree. Neither the lower part of the connector nor any equipment therebelow is directly connected to the platform legs or braces. The upper part of the connector is connected by crossbraces to the platform legs.

The upper and lower parts of the safety connector are connected to each other in a flange connection by studs and nuts which are of a selected material having a yield and ultimate strength slightly greater than the normal loads to which they are subjected. Under abnormal conditions, such as would cause the platform to move a substantial amount or turn over, these studs will break allowing the platform and all equipment above the upper part of the safety connector to move independently of the underwater Christmas tree and wellhead.

The safety connector is provided with flow nipples and groups of shorter hydraulic nipples which are screwed into the upper part and slidingly fit into the lower part. The groups of hydraulic nipples are arranged at approximately degree intervals so that the tipping of the platform and upper part of the safety connector in any direc tion will result in disengagement of at least one group of hydraulic nipples prior to disengagement of the flow nipples. Each group contains a number of nipples and corresponding sockets equal to the hydraulic functions performed therebelow. All hydraulic nipples are solid except those in line with the hydraulic runs from above the connector to the hydraulic equipment below, usually hydraulically operated valves. The sockets of each group in the lower part of the safety connector are connected for flow communication with the corresponding socket of the other group having the same hydraulic function.

In the event of severe platform damage which causes the parting of the two parts of the safety connector, the interruption of hydraulic pressure is affected through disengagement of at least one group of hydraulic nipples. The loss of hydraulic pressure causes the valve operators connected to the Christmas tree valves to fail-safe. Thus, the valves are closed, shutting-in the well immediately prior to flow nipple separation from the lower part of the safety connector. The well is then safely shut-in regardless of the platform damage and may be subsequently reconnected to the repaired platform for further production.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a schematic drawing showing one embodiment of the invention employed in an underwater well and platform arrangement;

FIGURE 2 is an elevational view in section of a safety connector acording to one embodiment of the invention taken along lines 22 of FIGURE 3; and

FIGURE 3 is a plan view of the safety connector of FIGURE 2 taken along lines 3--3 of FIGURE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to the schematic of FIGURE 1, the general layout of one type of platform installation embodying the invention will be described. A platform 1 above the water line 2 resting on support legs 3 is shown installed directly above an underwater wellhead 4 which is supported at subsurface 5 in any accepted manner. Attached to the wellhead 4 is a christmas tree, designated generally at 6, comprising hydraulically operated wing valve 7, master valve 8, casing valve 9 and choke landing nipple 10. The valve operators for valves 7, 8, and 9 are designed to fail-safe closed. The tree shown here is for single completion. Of course, multiple completions may be used, the single completion being shown for description purposes only. Directly above the Chirstmas tree 6 is safety connector 11, to be more fully described subsequently. The upper portion of connector 11 is connected to platform legs 3 by brace 12. A marine riser 13 may be connected above connector 11 for extension to platform 1. Other braces, such as 14, tie riser 13 to platform legs 3. Nothing below safety connector 11 is connected to the platform legs 3.

Extending upwardly through riser 13 is tubing riser 15 closed at its upper end by tubing access cap 16 and having a flow line branch 17. A tubing riser pressure indicator 18 may be provided. A casing annulus access H line 22 and casing pressure indicator 23 may also be installed. Hydraulic control lines 19 and are connected through safety connector 11 to wing, master and casing valve operators, and extend upwardly through riser 13 to a hydraulic power source (not shown) on the platform. Of course, other types of control may be used, such as electricity, and could easily be adapted for use with the described embodiment.

In operation, the upper and lower parts of safety connector 11 are easily separated. As earlier stated, the upper part is tied to platform legs 3 by braces 12. There may be four braces 12 at approximately 90 degree intervals. Each of these braces has just enough slack so that normal motions or vibrations will have no effect on the separation of the upper and lower parts of safety connector 11. However, abnormal movement of platform 1 and its legs 3 will separate the upper and lower parts, interrupting hydraulic control pressure to the operators of valves 7, 8 and 9 and subsequently breaking the connection of tubing riser 15 and production tubing in the well. The interruption of hydraulic control lines will cause the fail-safe operators to close valves 7, 8 and 9, consequently shutting in the well and preventing loss of production even though the platform may be completely destroyed.

Looking also now at FIGURES 2 and 3, connector 11 will be described in detail. The connector consists of two main parts, lower part 25 and upper part 26. Lower part 25 is connected to the upper part of a Christmas tree by means such as a flange or clamp or it may be integrally formed with the tree. Both parts are suitably bored to provide for tubing runs and hydraulic runs 36 and access to the casing annulus 35a if desired. Lower part 25 is counter-bored at 37 to receive tubing nipple 38 which is screwed into the tubing run bore 35 of the upper part. Sealing means such as O-rings 39' are provided on nipple 38. Lower part 25 is also counter-bored in the hydraulic runs 36 to form sockets 40 for receiving hydraulic nipples 41 which are screwed into the hydraulic runs 36 of upper part 26. The length of hydraulic nipples 41 is substantially less than flow nipples 38 for reasons to be subsequently disclosed. These nipples 41 are also provided with sealing means such as O-rings 42.

Looking at FIGURE 3, sockets 40 and blind sockets 43 are arranged in groups at approximately ninety degree intervals. Each group contains a number of sockets equal to the number of hydraulic functions required. In FIG- URE 3, sockets for two hydraulic functions are shown. For example, in use with the tree 6 of FIGURE 1, one function may be the operation of master and wing valves 8 and 7 and the other function may be the operation of casing valve 9. Of course, any number of functions may be used with the invention, requiring a corresponding number of sockets in the lower part 25 of connector 11. The sockets 40 and 43 of each group which represent the same hydraulic functions are interconnected by crossdrilling or the like. Only the nipples 41 which are in line with hydraulic runs 36 are hollow bored. All other nipples are solid and are screwed into tapped holes which register with corresponding blind sockets 43. Thus, the disengagement of one group of nipples from any group of sockets 40 or blind sockets 43 will result in a loss of pressure in hydraulic runs 36 causing the operators of corresponding valves to fail-safe or close. The same effect could be accomplished through electrical plugs and sockets if the valves were electrically operated.

Tubing run 35 and hydraulic run 36 are provided with connections 32 and 33 respectively for tubing riser and control lines such as riser 15 and control lines 19 and 20 of FIGURE 1. Means such as internal threads 34 may also be provided for connection of a marine protection riser such as 13 in FIGURE 1. Connecting links 31 provide means of tying to the platform legs through braces such as 12 in FIGURE 1. A ring joint 45 seals between the faces of the two main parts of the safety connector.

Lower part 25 and upper part 26 are tied together by studs 29 and nuts 30. These studs and nuts are preferably made of a metal whose yield and ultimate strength are only slightly more than the load applied to them under normal conditions. If the top part 26 of the safety connector receives a side thrust through connecting links 31 it creates a bending moment pivoting about the interface between upper and lower parts 25 and 26. When this moment reaches a predetermined value, the load on studs 29 reaches yield breaking the studs and allowing the upper part 26 to tilt over. As previously shown, when upper part 26 tilts, the hydraulic nipples 41 being shorter than flow nipples 38 will disengage first, allowing the hydraulic pressure to valve operator on the tree to bleed off. Thus, the valves close before the longer nipples 38 of the tubing run 35 and casing annulus access run are disconnected.

As can be seen from the foregoing description of; a preferred embodiment of the invention, the well can be safely shut-in and its connection with the surface severed before the platform has moved very much. Since there is no connection between the well and the platform below the safety connector, the platform could be completely turned over or removed without resulting damage to the well.

I claim:

1. Safety connector means for an underwater well having a platform thereabove and flow control means thereon, said safety connector being installed above said well and said flow control means near the floor of a body of water providing flow communication between said well and conduit means extending upwardly to said platform and providing control communication between said flow control means and a remote control station, a portion of said connector means being structurally attached to support members of said platform, another portion of said connector being rigidly attached to said well, said connector portions being adapted for disengagement from each other on abnormal movement of said platform to actuate said flow control means to shut-in said well and to free said platform for movement independent of said well.

2. The safety connector of claim 1 in which said connector comprises an upper part and a lower part connected to each other by connection means, said connection means having an ultimate strength slightly greater than the load applied to said connection means under normal conditions, said upper part being said portion attached to said platform support members, said connection means being breakable on said abnormal platform movement to allow said disengagement of said connector portions.

3. The safety connector of claim 2 in which said upper and lower parts have flow bore means passing therethrough to provide said flow communication and control line runs passing therethrough to provide said control communications, the flow bore means of one of said parts having nipple means projecting therefrom into a sliding fit with the flow bore means of the other of said parts, the length of said nipple means being such as to allow flow interruption on said disengagement only after said control communication is first interrupted to shut-in said well.

4. The safety connector of claim 3 in which said control line runs are conduit means, the conduit means of one of said parts having other nipple means projecting therefrom into a sliding fit with the conduit means of the other of said parts, said other nipple means being substantially shorter than said flow bore nipple means.

5. The safety connector of claim 4 in which there are solid nipple means projecting from one of said part into a sliding fit with blind socket means of the other part arranged at regular intervals around the interface of said parts, there being interconnecting passages between said blind sockets and said conduit means.

6. Safety connector means for an offshore well having a wellhead supported near the floor of a body of Water and a production platform thereabove, said connector means being installed near said wellhead, providing flow communication between said wellhead and flow conduit means extending upwardly to said platform and providing control communication between said platform and fiow control means located below said connector means, said connector means comprising a first portion structurally tied to support members of said platform and a second portion rigidly attached to said wellhead, said portions being bored with at least one flow run to provide said flow communication, the flow run of one of said portions having flow nipple means rigidly projecting therefrom, the flow run of the other of said portions having a counter-bored socket to slidingly receive the project on of said flow nipple means, said portions having at least one hydraulic run bored in each of said connector portions to provide said control communication, the hydraulic run of one of said portions having hydraulic nipple means rigidly projecting therefrom, the hydraulic run of the other portion having a counterbored socket to slidingly receive the projection of said hydraulic nipple means, the projection of said hydraulic nipple means being substantially less than the projection of said flow nipple means, said first and second connector portions being adapted for disengagement from each other on abnormal movement of said platform to interrupt said flow and control communication and to actuate said flow control means to shut-in said well and to free said platform, said first connector portion and all well equipment thereabove from said second connector portion and all well equipment therebelow.

7. The connector means of claim 6 in which there are a plurality of groups of hydraulic nipple means and corresponding sockets spaced at intervals around the interface of said first and second portions, each group having at least one of said hydraulic nipple means and sockets for each hydraulic function required for said flow control means, the socket of each of said groups corresponding to the same hydraulic function being interconnected for flow communication therebetween.

8. The safety connector means of claim 6 in which said first portion and said second portion are initially held together by connection means whose yield and ultimate strength is slightly more than its load during normal movements of said platform but less than its load during abnormal movements of said platform.

9. The connector of claim 8 in which said first and second portions of said connector means comprises flange means and said connection means comprises a plurality of studs and nuts linking said connector means portions through said flange means.

10. Safety connector means for use in an underwater well having a wellhead supported near the floor of a body of water and a production platform thereabove, said connector means being installed above an underwater Christmas tree surmounted on said Wellhead, said Christmas tree having remotely operable flow controls thereon, said connector means comprising an upper part and a lower part connected to each other by studs and bolts through flange means, each of said connector parts having flow conduit means providing flow communication between said Christmas tree and tubing means extending upwardly to said platform, the flow conduit means of one of said parts having flow nipples projecting therefrom into a sliding fit with the flow conduit means of the other of said parts, each of said parts also having control line means providing control communication between said remotely operable flow controls and control means on said platform, said upper part of said connector means being tied to the support legs of said platform, the strength of said studs and bolts being of such a value as to allow breakage of said studs and nuts on abnormal movement of said platform to allow disengagement of said upper and lower connector parts to first interrupt said control communication causing said flow control means to shut-in said well and to release said platform for movement independent of said wellhead and Christmas tree.

11. The safety connector of claim 10 in which said control line means is a number of hydraulic conduit means equal to at least the number of hydraulic functions required to operate said flow control means, the hydraulic conduit means of one of said connector parts having hydraulic nipples projecting therefrom into a sliding fit with the hydraulic conduit means of the other of said parts,

the projected length of said hydraulic nipples being less than the projected length of said flow nipples.

12. The safety connector of claim 11 in which there are a plurality of groups of solid nipples projecting from one of said parts into a sliding fit with corresponding groups of blind sockets in said other part at regular intervals around the interface of said connector parts, each of said groups containing at least one blind socket corresponding to the said hydraulic conduit for each of said hydraulic functions and being interconnected therewith through passage means.

13. The safety connector of claim 12 in which all of said nipples and their corresponding said sockets or conduits are provided with sealing means therebetween.

14. Safety connector means for an underwater well having a platform resting on legs supported at the floor of a body of water and flow control means at the well head of said well near said floor, said safety connector being installed above said wellhead and said flow control means near the floor of said body of water providing flow c mmunication between said wellhead and conduit means extending upwardly to said platform and providing control communication between said flow control means and a remote control station, an upper portion of said connector means being attached to the legs of said platform by structural members, a lower portion of said connector 7 being rigidly attached to said Wellhead, said connector portions being adapted for disengagement from each other on abnormal movement of said platform to actuate said flow control means to shut-in said well and to free said platform for movement independent of said wellhead and said flow control means.

15. Safety connector means as set forth in claim 14, said connector portions being joined at a common interface by frangible connecting means, said upper portion being adapted to pivot about said interface on said abnormal movement of said platform to break said frangible connecting means and allow said disengagement of said connector portion.

References Cited UNITED STATES PATENTS 6/1937 Cline 2852 6/1937 Boyles 2852 X 12/1959 Nicolson 166- 5 11/1965 Hayes 166.5 X 3/1966 Shaffer 166-.5 X 7/1967 Johnson 166-.6 5/1968 Richardson 166.5

U.S. Cl. X.R. 

